This copy was signed by Marcel Duchamp in Milan, 1964. Three pieces of metre-long thread are dropped from a height of one metre. How they fall is of course subject to pure chance. After they have fallen they are fixed with varnish. Three rulers are sawn up to preserve the result of the random fall. These threads reappear in The Great Glass, now in lead. No event can be completely controlled in art - you have to have chance on your side.